Hand held distribution apparatuses are known in the art as useful tools in laboratories. They are mainly used for distributing one or more samples to a target container, for example a plate with a plurality of wells. There are hand-operated dispensers and pipettes including single-channel (having a single release channel) and multi-channel (having several release channels) devices as described for example in application US 2009/0274587 A1. Their release channels allow the release and normally also the uptake of fluid samples.
Pipettors (also called pipettes), as the distribution apparatuses of primary interest in the context of this application, are understood to be devices used to transport a measured volume of liquid. The sample volume, which is released by the device by a single operation, may (substantially) correspond to the sample volume aspirated into the device. However, there are also pipettes that are capable of aspirating a measured volume of liquid and then releasing measured partial volumes (of the aspirated volume) by single operations. In this case the aspirated sample volume corresponds to several release doses and is therefore released stepwise.
Electronic versions of such devices are also known. They are often programmable either manually via a user interface or via a data interface that may be connected to a computer (see for example U.S. Pat. Nos. 6,778,917 B1 and 5,343,769, European application EP 0 864 364A4 The programming either contributes to the control of the device's operation or it allows for data collection during operation. Operating such distribution apparatuses normally includes moving the apparatus manually from the source container where the sample is aspirated to the target container where it is released. Target containers often contain a multitude of receptacles that need to be filled in sequence which requires a considerable number of operations. The process is thus prone to errors and requires a lot of hand work.
Automated pipetting apparatuses as described for example in US applications 2011/0268627 A1 or US 2011/0296931 A1—that perform the aspiration of samples at the source container, their transfer to the target container, and the release of the samples to the correct part of the target container (e.g. a certain number of wells) allow for higher precision and increased throughput. However, such robots are expensive pieces of laboratory equipment and often difficult to operate since programming them is a rather complex task. They are either fully automated or semi-automated. Robots with a semi-automated mode of operation like those described in US 2011/0268627 A1 and US 2011/0296931 A1 may be manually directed by controls installed on the device like buttons, wheels, or a control handle. As a consequence of their automated nature they require less or no it from the operator once they have been programmed. However, they are stationary and thus less versatile than hand-held devices.
WO 2012/069925 A1 describes a fully automated programmable robot that utilizes hand-held mechanical pipettes. The pipettes may be removed from the robot and operated by hand. Due to the fact that the robot needs to be capable of performing all process steps otherwise carried out by a human operator it is by nature complex and expensive. As a result, devices of intermediate complexity have been developed like the one taught in U.S. Pat. No. 5,415,060 which comprises a movable holder for a well plate and a fixed support bridge for supporting a pipettor. The distribution system according to US 2011/0209564 A1 improves on the aforementioned device and further comprises a mechanism for guiding the operator's hand during sample distribution and thereby increases precision. The latter document teaches a positioning device adapted for holding a manually operated distribution apparatus (pipettor or dispenser) and a target container. The distribution apparatus in its mounted state is movable relative to the target container. The relative movement is however limited wherein the limitation is adjusted automatically upon each distribution step. Thus the device takes over the decision of the person using a manually operated distribution apparatus to decide which target position on a well plate has to be approached next. The means for limiting movement, which are part of the positioning device, can provide electrical control components, such as circuits and programmable digital or analogue controls. It is also mentioned that the sample distribution system may be semi- or fully automated and/or a robot and that it may be operated semi- or fully automatically, electrically, hydraulic, pneumatic etc. However, few details are provided in this respect since the document focuses on a manually actuable apparatus which is preferably usable without an external electrical energy source. A device as described in US 2011/0209564 A1 still requires the operator's presence and attention. This also applies to the device disclosed in DE 10 2008 010 267 A1 which teaches an apparatus similar to the one taught in US 2011/0209564. The apparatus comprises a locking bar with periodical locking positions and a marking unit which is movable at a guide and has a marking pin to fix the bar at one locking position. A marking position is indicated at a marking element or a slider and a coupling unit has a coupling pin for fixing the position of the pipette unit in the slider at the marking unit in the marking position. The mechanism thus guides the operator's hand during sample distribution, by restricting its freedom of movement. It is also mentioned that the apparatus may be automatic or semi automatic and may for this purpose comprise a number of electronic or electric components. Since they are described as parts of the stationary guiding device this would make the apparatus a robot like the ones described above with the exception that the programming and control of the automated variant of the device taught in DE 10 2008 010 267 A1 is performed on and by a computer connected to the apparatus via an interface.